A134295 - cp's OEIS frontend

A134295 a(n) = Sum_{k=1..n} ((n-k)!*(k-1)! - (-1)^k).

n	a(n)
1	2
2	2
3	6
4	16
5	65
6	312
7	1813
8	12288
9	95617
10	840960
11	8254081
12	89441280
13	1060369921
14	13649610240
15	189550368001
16	2824077312000
17	44927447040001
18	760034451456000
19	13622700994560001
20	257872110354432000
21	5140559166898176001

[2, 2, 6, 16, 65, 312, 1813, 12288, 95617, 840960, 8254081, 89441280, 1060369921, 13649610240, 189550368001, 2824077312000, 44927447040001, 760034451456000, 13622700994560001, 257872110354432000, 5140559166898176001]

cp's OEIS Frontend

A134295 a(n) = Sum_{k=1..n} ((n-k)!*(k-1)! - (-1)^k).

Table of values

List of values